1. Field of the Invention
The present invention relates to a lens-fitted photographic film unit capable of changing an aperture in accordance with a photography mode.
2. Background Arts
A variety of lens-fitted photographic film units with preloaded photographic films have been on the market. Some of them are provided with flash devices integrated therein so as to be capable of photographing in a dark place. There also is the lens-fitted photographic film unit of a mode changeover type that enables to change an EV (exposure value) in accordance with a photographing condition by selecting a photography mode so as to photograph both in a bright place and in the dark place. This lens-fitted photographic film unit of the mode changeover type uses a high speed photographic film for the purpose of improving the description of the background photographed in the dark place (Japanese Patent Laid-Open Publication Number 11-64951).
The lens-fitted photographic film unit with the flash device is preloaded with the photographic film of ISO800 and has a shutter speed at 1/140 minute and an aperture value of f10, so as to have a correct EV at 10.8 with reference to ISO100. It is thus possible to correctly expose a main subject within a relatively short distance by emitting the flash light at nighttime or in the dark place such as an indoor place.
Although such lens-fitted photographic film unit with the flash device can photograph the main subject at an approximately correct exposure by emitting the flash light, it causes extreme under-exposure of the background where beyond the reach of the flash light.
A lens-fitted photographic film unit of mode changing type is known to be provided with a shutter speed changing mechanism and a stop changeover mechanism in addition to the flash device, and has the high speed photographic film preloaded therein (Japanese Patent Laid-Open Publication Number 2003-344914). This lens-fitted photographic film unit has three photography modes: a daylight mode (no flash light) for photographing in the bright place such as an outdoor place in daylight, a daylight flash mode (with flash light), and a night flash mode for photographing in the dark place by emitting the flash light to the main subject and describing the background at suitable density.
A high shutter speed and a small aperture are employed in the daylight mode and the daylight flash mode stated above, while a low shutter speed and a large aperture are employed in the night flash mode. The photographic film of ISO800 is preloaded in this lens-fitted photographic film unit. The shutter speed is predetermined to be at, for example, 1/120 sec and the aperture value is predetermined to be, for example, f14 in the daylight mode and the daylight flash mode. In the night flash mode, the shutter speed is predetermined at, for example, 1/45 sec and the aperture value is predetermined to be, for example, f5.6.
However, the lens-fitted photographic film unit of mode changing type has a problem of that it is hard to know the selected photography mode from its appearance. In order for the user to be able to easily observe the selected mode, the lens-fitted photographic film unit with the flash device disclosed in Japanese Patent Laid-Open Publication Number 11-64951 protrudes a light guide, which displays charging condition of the flash circuit, from the top face of a camera body in a flash photography mode.
In addition, the lens-fitted photographic film unit of mode changing type disclosed in Japanese Patent Laid-Open Publication Number 2003-344914 indicates the selected photography mode by giving no sign in the daylight photography mode, protruding the light guide from the top face of the camera body in the daylight flash mode, and inserting an index plate in front of a front viewfinder window in the night flash mode.
However, if the user forgets to change the photography mode and photographs with the lens-fitted photographic film unit of mode changing type, the photographing is performed in the photography mode set in the previous photographing. It is likely for the user to forget to change the photography mode before photographing, since a photography mode selection lever of the above lens-fitted photographic film unit is provided on the front face of the camera body. As for the lens-fitted photographic film unit disclosed in Japanese Patent Laid-Open Publication Number 11-64951, even photographing in inappropriate photography mode does not have a substantial influence on the exposure, since the difference between the two modes are only whether emitting the flash light or not. However, photographing in an improper photographing mode with the lens-fitted photographic film unit disclosed in Japanese Patent Laid-Open Publication Number 2003-344914 can result in failure, as the exposure is changed based on the photography mode.